Potterton Netaheat profils 50e fan but nothing else!!

[nwlondon]

Hello I have a potterton netaheat profile 50e probably about 15 years old this is the first time something has gone wrong!

Whats happens is when I turn on the heating or hot water from the honeywell control pad the fan comes on for about 20 or so seconds and then stops then comes on for 20 second or so then stops. It keeps doing this and obvously I have no hot water or rads working. fortunatly I have hot water through the emersion !

when it used to work the process was fan on .... ignition (ticking noise of spark) then a poof ! noise of the gas lighting and I could see a blue flame through the round glass window

I have changed the fuse in the un switched spur (3amp)
I have tested all the electrical cables with my multi meter all seam ok and fuse on pcb tests ok
I have looked at all the rubber tubes checked for holes or tears all seam ok. I have blown (by mouth) through the tubes and all clear none bent or stopping air flow.

I personally thing it is either the air pressure switch not working properly or pcb needs changing?

So can anyone help me please?

 

[heatingman]

PCB/Control box, common fault

 

[Agile]

Probably the PCB but also might be the air pressure switch system or a dirty fan!.

Tony

 

[nwlondon]

I changed the PCB and it all works lovely now it cost me 25 quid for a refurb but it works and Im happy

 

[nwlondon]

as baovr it worked for a good 10 hours got up this morning all turned on but not working!! Is it possable the honeywell 3 way switch which seam loose the springs are not very taught could be faulty? I have also not changed the air pressure switch??. The latest is the boile is not firing not even the fan comes on now?!!!!

 

[nwlondon]

It seam (well twice) to intermitanty work. I have changed the PCB and it worked for about 10 hours both hot water and heating. Then everything cooled down and then does not work at all.

I have checked all eletrical points with multi meter and looked at all the tube again all seam ok

My question is can the air pressure switch which is quiet old it a sealed white plastic round one be intermittant ? I have a new one which I got it is in kit form its a pressure switch pro 30 80e I took the original one to the plumbers merchant and he sold me this. Any ideas??? please

Current sate of play its all turned on but not even the fan kicks in and nothing heating.

 

[nwlondon]

It was the air pressure switch chamged and now the system is up and running thank you to all who helped me